Drainage systems employing preassembled drainage elements

ABSTRACT

Pairs of preassembled drainage units are disposed in the bottom of a trench in laterally spaced apart relation with each drainage unit having an integral flap extending outwardly into overlapping relation with the flap of an adjacent drainage unit to form a chamber below the flaps and between the drainage units. An adapter can be used at one end of the drainage units to space the drainage units apart and to seal off the end from the entry of dirt and debris.

This application claims the benefit of Provisional Patent Application No. 61/200,668 filed Dec. 2, 2008.

This invention relates to a drainage system employing preassembled drainage elements, such as described in U.S. Pat. Nos. 6,857,818; 6,988,852; 7,178,224 and 7,419,333 and pending U.S. patent application Ser. No. 11/106,108 filed Apr. 14, 2005, Ser. No. 11/248,753 filed Oct. 12, 2005, Ser. No. 11/506,332 filed Aug. 18, 2006, Ser. No. 11/509,405 filed Aug. 24, 2006, Ser. No. 11/591,420 filed Nov. 20, 2006, Ser. No. 11/637,534 filed Dec. 12, 2006 and Ser. No. 12/001,703 filed Dec. 12, 2007.

In some cases, drainage systems employ at least pairs of preassembled drainage units within a trench or ditch for drainage purposes. Typically, the drainage units are arranged in side-by-side abutting relation and may or may not be covered by another element. It has also been known from U.S. Pat. No. 6,705,800 that preassembled drainage units may be laterally spaced from each other to define an open storage chamber with a prefabricated plastic cover placed on top of and spanning the laterally spaced pipes to prevent top dirt fill from falling down into the storage chamber.

However, the known drainage systems require proper positioning of the preassembled drainage units in order to place a prefabricated plastic cover in proper position.

Accordingly, it is an object of the invention to provide a drainage system of preassembled drainage units that are laterally spaced apart with a chamber therebetween that is protected from the entry of soil in an efficient manner.

It is another object of the invention to provide a drainage system of preassembled drainage units that are laterally spaced apart with a chamber therebetween that does not require prefabricated covers.

Briefly, the invention provides a drainage system comprising at least one pair of preassembled drainage units disposed in the bottom of a trench in laterally spaced apart relation with each drainage unit having an integral flap extending outwardly thereof into overlapping relation with the flap of an adjacent drainage unit to form a chamber below the flaps and between the drainage units as well as a layer of backfill disposed over the drainage units and the flaps.

The preassembled drainage units are disposed in spaced apart parallel relation with a flap on each drainage unit being secured to a like flap on the other unit in bridging relation to the space between the two drainage units.

Typically, each drainage unit includes a sleeve having an upper peripheral portion formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering the unit, a lower peripheral portion, such as of netting, at least one flap extending outwardly of the sleeve and a mass of light weight synthetic aggregate disposed within the sleeve. The units are placed in the trench in spaced relation to each other with the flaps of each unit disposed in overlapping relation to a flap of an adjacent unit. In this arrangement, the overlying flaps serve to space the drainage units apart in parallel relation thereby creating a larger volume or space below and between the drainage units for the passage of effluent from the drainage units into the ground below. This arrangement provides for more square feet of drainage under the units than a conventional array of drainage units that are placed in contact with each other. Said another way, the arrangement uses a lesser number of drainage units than a conventional array to obtain the same amount of square feet of drainage under the units.

Each drainage unit may be provided or not with a perforated pipe that extends the length of the unit in a conventional manner or only part way into the unit.

In one embodiment, a pipe may project into the space between two drainage units for a short distance in order to introduce an effluent into the space between the drainage units.

An adapter may be disposed at the forward end of two or more parallel drainage units in order to initially space the drainage units apart and to seal off the forward ends of the drainage units from the entry of dirt and debris. Such an adapter may also have a suitable fitting to allow the entry of a perforated pipe or non-perforated pipe into the space between the drainage units.

A bridge may also be disposed between two drainage units to support the backfill that is typically filled into the trench after placement of the drainage units. Such a bridge may be arch-shaped for purposes of strength and perforated to allow the passage of water.

FIG. 1 illustrates a cross-sectional view of a drainage system employing pairs of drainage units in accordance with the invention;

FIG. 2 illustrates a cross-sectional view of a modified drainage system employing pairs of drainage units and an entry pipe in accordance with the invention;

FIG. 3 illustrates a perspective view of a front end of the drainage system of FIG. 2;

FIG. 4 illustrates a perspective view of an adaptor used in accordance with the invention;

FIG. 5 illustrates a cross-section of a further modified drainage system employing an arch-shaped bridge in accordance with the invention;

FIG. 6 illustrates a cross-section of a modified bridge in accordance with the invention;

FIG. 7 illustrates a cross-section of a further modified bridge in accordance with the invention; and

FIG. 8 illustrates a perspective view of the bridge of FIG. 5.

Referring to FIG. 1, the drainage system includes a pair of preassembled drainage units 10, 11, each of which is made as described in pending US Patent Application entitled Drainage Element and Apparatus and Method for Making Same and filed Nov. 3, 2008. For example, each drainage unit 10, 11 has a sleeve having an upper peripheral portion 12 formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering the unit, a lower peripheral portion 13, such as of netting, an integral flap 14 extending outwardly of the sleeve and a mass of light weight synthetic aggregate (not shown) disposed within the sleeve. The flap 14 is formed by overlying longitudinal edges of the peripheral portions 12, 13 and extends along the length of the drainage unit.

Each unit 10, 11 has an outer diameter of 12 inches and a length of 10 feet. As shown, one drainage unit 11 has a perforated pipe 15 extending therethrough while the other drainage unit 10 is free of any perforated pipe.

The drainage units 10, 11 are disposed in the bottom of a trench 16 and are covered by backfill 17.

The flaps 14 of the adjacent drainage units 10, 11 are disposed in overlapping relation and are secured together to maintain the spacing between the drainage units 10, 11 and to thereby form a chamber 18 below the flaps 14 and between the drainage units 10, 11. The pipe 15 allows effluent into the aggregate within the drainage unit 11 from whence the effluent flows into chamber 18 between the drainage units 10, 11 and under the bridge defined by the flaps 14.

The drainage units 10, 11 may be secured together via the flaps 14 before shipment to a work site. This allows for an ease of handling and shipping.

Referring to FIG. 2, wherein like reference characters indicate like parts as above, the drainage system may be provided with a perforated pipe 15 disposed between the drainage units 10,11 to pass effluent, e.g. from a septic tank (not shown) into the chamber 18. Such a pipe 15 need only extend a short distance into the space 18, for example from 6 to 12 inches or whatever length is desired.

Referring to FIGS. 3 and 4, wherein like reference characters indicate like parts as above, the forward ends of the drainage units 10, 11 are provided with an adapter 19 that allows effluent into the chamber 18 but keeps dirt out of the drainage units 10, 11. As indicated, the adapter 19 is of ovate shape to fit, as a sleeve, over the ends of the drainage units 10,11 and to maintain the drainage units 10,11 in spaced apart relation. In addition, one end of the adapter 19 is closed to keep dirt out of the ends of the drainage units 10, 11 and is provided with an opening 20 to allow a pipe to pass through for the introduction of an effluent into the chamber 18 between the drainage units 10, 11 and under the bridge defined by the flaps 14.

In the system of FIG. 4, the pipe for introducing the effluent into the chamber 18 need only extend 6 to 12 inches into the chamber 18. Where the pipe is perforated, a length of membrane material may be laid over the pipe to keep dirt out. Also, the next pairs of drainage units (not shown) may be placed in the trench in butted relation to the drainage units 10, 11 with piece of membrane material draped over the abutted ends of the drainage units to keep dirt out of the chamber 18.

Referring to FIG. 5, the space between the drainage units 10,11 may be maintained by using a bridge 21 to support the backfill 17 (see FIG. 1) that is typically filled into the trench 16 after placement of the drainage units. Such a bridge 21 may be arch-shaped for purposes of strength and perforated to allow the passage of water or of hemi-spherical shape or of any other suitable shape. As indicated, the bridge 21 is placed loosely on top of the flaps 14 with the ends of the bridge 21 abutting the respective drainage units 10, 11.

As shown in FIG. 6, the ends 22 of the bridge 21 may be turned in an outwardly directed direction or as shown in FIG. 7, the ends 22′ of the bridge 21 may be turned in an inwardly directed direction.

As shown in FIG. 8, the bridge 21′ may be corrugated with transverse ribs 23 for strength. 

1. A drainage system comprising at least one pair of preassembled drainage units disposed in the bottom of a trench in laterally spaced apart relation, each said drainage unit having an integral flap extending outwardly thereof into overlapping relation with said flap of an adjacent drainage unit to form a chamber below said flaps and between said drainage units; and a layer of backfill disposed over said drainage units and said flaps.
 2. A drainage system as set forth in claim 1 wherein said flaps are secured together to maintain a spacing between said drainage units.
 3. A drainage system as set forth in claim 1 wherein each said drainage unit includes a sleeve having an upper peripheral portion formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering said drainage unit, a lower peripheral portion of netting and a mass of light weight synthetic aggregate disposed within said sleeve.
 4. A drainage system as set forth in claim 3 further comprising a perforated pipe extending through said mass of aggregate of at least one of said drainage units.
 5. A drainage system as set forth in claim 3 further comprising a perforated pipe extending through said space between said drainage units.
 6. A drainage system as set forth in claim 3 further comprising an adapter at one end of said drainage units to space said drainage units apart and to seal off said one end of said drainage units from the entry of dirt and debris.
 7. A drainage system as set forth in claim 6 further comprising a perforated pipe passing through said adapter into the space between said drainage units.
 8. A drainage system as set forth in claim 1 further comprising a bridge disposed in parallel between said drainage units to support said backfill.
 9. A drainage system as set forth in claim 8 wherein said bridge is arch-shaped and perforated to allow the passage of water.
 10. A drainage system as set forth in claim 8 wherein said bridge is placed loosely on top of said overlying flaps 14 with ends of said bridge abutting said respective drainage units.
 11. A drainage system as set forth in claim 10 wherein said bridge has longitudinally extending ends of the bridge turned in one of an outwardly and inwardly directed direction.
 12. A preassembled drainage assembly comprising at least one pair of preassembled drainage units, each said drainage unit having an integral flap extending outwardly thereof into overlapping secured relation with said flap of an adjacent drainage unit to secure said drainage units together.
 13. A preassembled drainage assembly as set forth in claim 12 wherein each said drainage unit includes a sleeve having an upper peripheral portion formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering said drainage unit, a lower peripheral portion of netting and a mass of light weight synthetic aggregate disposed within said sleeve.
 14. A preassembled drainage assembly as set forth in claim 13 wherein each flap is formed by overlying longitudinal edges of said peripheral portions of a respective drainage unit and extends along the length of a respective drainage unit. 